An embodiment of the present invention relates to a backlight module.
A liquid crystal display, which generally includes a liquid crystal panel and a backlight module, is a flat panel display that has been commonly used. The backlight module is an important component for supplying the liquid crystal panel with light in the liquid crystal display.
FIG. 4 is a diagram showing a structure of a backlight module. As shown in FIG. 4, the backlight module includes a reflective plate 25, a light guide plate 24, an optical sheet 23, a light source 26, a circuit substrate 27, a metal rear plate 21, and an outer frame 22. The light guide plate 24 is located above the reflective plate 25, the optical sheet 23 is located above the light guide plate 24, the light source 26 is disposed on the circuit substrate 27, the light source 26 and the circuit substrate 27 are disposed within a chamber 29 surrounded by the metal rear plate 21 and the light guide plate 24, the light source 26 and the circuit substrate 27 are disposed on a side of the light guide plate 24, the circuit substrate 27 is fixed on the metal rear plate 21 by a heat dissipation glue 18, and the outer frame 22 is mounted on the metal rear plate 21.
When the light source 26 is turned on, a large amount of heat will be generated. The generated heat is transferred to the metal rear plate 21 via the circuit substrate 27 and the heat dissipation glue 18, and then transferred to the outside of the backlight module by the metal rear plate 21. As the liquid crystal display has been becoming larger, higher luminance of the light source is required, and it has to use a light source with higher power or more light sources for the backlight module to meet the requirement of the liquid crystal display. However, the light source with higher power or more light sources will generate much heat. The structure and the heat dissipation mode of the above backlight module can not meet the requirement for heat dissipation of the large-size liquid crystal display. With regard to the large-size liquid crystal display, the heat dissipation efficiency of the backlight module is low, so that the heat is accumulated in the backlight module. As a result, the light source is damaged and the life span of the backlight module is reduced.